// WindowsProject1.cpp : Defines the entry point for the application.
//

#include "framework.h"
#include "WindowsProject1.h"
#pragma comment(lib, "Msimg32.lib")

#define MAX_LOADSTRING 100

// Global Variables:
HINSTANCE hInst;                                // current instance
WCHAR szTitle[MAX_LOADSTRING];                  // The title bar text
WCHAR szWindowClass[MAX_LOADSTRING];            // the main window class name

// Forward declarations of functions included in this code module:
ATOM                MyRegisterClass(HINSTANCE hInstance);
BOOL                InitInstance(HINSTANCE, int);
LRESULT CALLBACK    WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK    About(HWND, UINT, WPARAM, LPARAM);
void Paint(HDC hdc);


int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
                     _In_opt_ HINSTANCE hPrevInstance,
                     _In_ LPWSTR    lpCmdLine,
                     _In_ int       nCmdShow)
{
    UNREFERENCED_PARAMETER(hPrevInstance);
    UNREFERENCED_PARAMETER(lpCmdLine);

    // TODO: Place code here.

    // Initialize global strings
    LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
    LoadStringW(hInstance, IDC_WINDOWSPROJECT1, szWindowClass, MAX_LOADSTRING);
    MyRegisterClass(hInstance);

    // Perform application initialization:
    if (!InitInstance (hInstance, nCmdShow))
    {
        return FALSE;
    }

    HACCEL hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_WINDOWSPROJECT1));

    MSG msg;

    // Main message loop:
    while (GetMessage(&msg, nullptr, 0, 0))
    {
        if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }

    return (int) msg.wParam;
}



//
//  FUNCTION: MyRegisterClass()
//
//  PURPOSE: Registers the window class.
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
    WNDCLASSEXW wcex;

    wcex.cbSize = sizeof(WNDCLASSEX);

    wcex.style          = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc    = WndProc;
    wcex.cbClsExtra     = 0;
    wcex.cbWndExtra     = 0;
    wcex.hInstance      = hInstance;
    wcex.hIcon          = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_WINDOWSPROJECT1));
    wcex.hCursor        = LoadCursor(nullptr, IDC_ARROW);
    wcex.hbrBackground  = (HBRUSH)(COLOR_WINDOW+1);
    wcex.lpszMenuName   = MAKEINTRESOURCEW(IDC_WINDOWSPROJECT1);
    wcex.lpszClassName  = szWindowClass;
    wcex.hIconSm        = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

    return RegisterClassExW(&wcex);
}

//
//   FUNCTION: InitInstance(HINSTANCE, int)
//
//   PURPOSE: Saves instance handle and creates main window
//
//   COMMENTS:
//
//        In this function, we save the instance handle in a global variable and
//        create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   hInst = hInstance; // Store instance handle in our global variable

   HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr, hInstance, nullptr);

   if (!hWnd)
   {
      return FALSE;
   }

   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);

   return TRUE;
}

//
//  FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
//
//  PURPOSE: Processes messages for the main window.
//
//  WM_COMMAND  - process the application menu
//  WM_PAINT    - Paint the main window
//  WM_DESTROY  - post a quit message and return
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case WM_COMMAND:
        {
            int wmId = LOWORD(wParam);
            // Parse the menu selections:
            switch (wmId)
            {
            case IDM_ABOUT:
                DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
                break;
            case IDM_EXIT:
                DestroyWindow(hWnd);
                break;
            default:
                return DefWindowProc(hWnd, message, wParam, lParam);
            }
        }
        break;
    case WM_PAINT:
        {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(hWnd, &ps);
            // TODO: Add any drawing code that uses hdc here...
            FillRect(hdc, &ps.rcPaint, (HBRUSH)GetStockObject(GRAY_BRUSH));
            Paint(hdc);
            EndPaint(hWnd, &ps);
        }
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}

// Message handler for about box.
INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
    UNREFERENCED_PARAMETER(lParam);
    switch (message)
    {
    case WM_INITDIALOG:
        return (INT_PTR)TRUE;

    case WM_COMMAND:
        if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
        {
            EndDialog(hDlg, LOWORD(wParam));
            return (INT_PTR)TRUE;
        }
        break;
    }
    return (INT_PTR)FALSE;
}

HBITMAP loadBmp(const char* fileName) {
	return (HBITMAP)LoadImageA(::GetModuleHandle(NULL), fileName, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
}
void freeBmp(HBITMAP hBitmap) { if (hBitmap) ::DeleteObject(hBitmap); }

PBITMAP getBitmap(HBITMAP hBitmap) {
    if (!hBitmap) return NULL;
    PBITMAP bmp = new BITMAP;
    if (::GetObject(hBitmap, sizeof(BITMAP), bmp)) {
        if (!bmp->bmBits) {
            int len = bmp->bmWidth * bmp->bmHeight * bmp->bmBitsPixel / 8;
            if (len > 0) {
                bmp->bmBits = new char[len];
                if (bmp->bmBits) {
                    ::ZeroMemory(bmp->bmBits, len);
                    if (::GetBitmapBits(hBitmap, len, bmp->bmBits)) {
                        return bmp;
                    }
				}
            }
		}
		if (bmp->bmBits) delete bmp->bmBits;
    }
    if (bmp) delete bmp;
    return NULL;
}
void freeBitmap(PBITMAP pBitmap) {
    if (!pBitmap) return;
    if (pBitmap->bmBits) {
        delete pBitmap->bmBits;
        pBitmap->bmBits = NULL;
    }
    delete pBitmap;
}

HBITMAP create32bitmap(int w, int h, LPVOID *pData) {
    if (w <= 0 || h <= 0 || !pData) return NULL;
	BITMAPINFO bmi;
	::ZeroMemory(&bmi, sizeof(BITMAPINFO));
	bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
	bmi.bmiHeader.biWidth = w;
	bmi.bmiHeader.biHeight = -h;
	bmi.bmiHeader.biPlanes = 1;
	bmi.bmiHeader.biBitCount = 32;
	bmi.bmiHeader.biCompression = BI_RGB;
	return ::CreateDIBSection(NULL, &bmi, DIB_RGB_COLORS, pData, NULL, 0);
}

void alpha_draw_bitmap(HDC hdc, HBITMAP hBitmap, const RECT &rc, bool bAlpha) {
    if (!hdc || !hBitmap) return;

	BLENDFUNCTION bf = { AC_SRC_OVER, 0, 255, bAlpha ? AC_SRC_ALPHA : AC_SRC_OVER };

	HDC hCloneDC = ::CreateCompatibleDC(hdc);
	HBITMAP hOldBitmap = (HBITMAP) ::SelectObject(hCloneDC, hBitmap);
	::SetStretchBltMode(hdc, HALFTONE);

	::AlphaBlend(hdc, rc.left, rc.top, rc.right - rc.left, rc.bottom - rc.top
		, hCloneDC, 0, 0, rc.right - rc.left, rc.bottom - rc.top, bf);

	::SelectObject(hCloneDC, hOldBitmap);
	::DeleteDC(hCloneDC);
}
void draw_bitmap(HDC hdc, HBITMAP hBitmap, const RECT& rc) {
	HDC hCloneDC = ::CreateCompatibleDC(hdc);
	HBITMAP hOldBitmap = (HBITMAP) ::SelectObject(hCloneDC, hBitmap);
    ::BitBlt(hdc, rc.left, rc.top, rc.right - rc.left, rc.bottom - rc.top
        , hCloneDC, 0, 0, SRCCOPY);
	::SelectObject(hCloneDC, hOldBitmap);
	::DeleteDC(hCloneDC);
}
HBITMAP calculateBmp(HBITMAP srcBmp, HBITMAP maskBmp) {
    LPVOID pData = NULL;
	auto srcInfo = getBitmap(srcBmp);
	auto maskInfo = getBitmap(maskBmp);
    if (srcInfo && maskInfo && srcInfo->bmWidth == maskInfo->bmWidth && srcInfo->bmHeight == maskInfo->bmHeight
        && srcInfo->bmBitsPixel == 32 && maskInfo->bmBitsPixel == 32) {
		auto hBitmap = create32bitmap(srcInfo->bmWidth, srcInfo->bmHeight, &pData);
        if (hBitmap && pData) {
			int nWidth = srcInfo->bmWidth;
			int nHeight = srcInfo->bmHeight;
			//
			LONG nPixels = nWidth * nHeight;
			RGBQUAD* pSrc = (RGBQUAD*)srcInfo->bmBits;
			RGBQUAD* pMask = (RGBQUAD*)maskInfo->bmBits;
			RGBQUAD* pRGB = (RGBQUAD*)pData;
			for (; nPixels > 0; --nPixels, ++pRGB, ++pSrc, ++pMask) {
				pRGB->rgbReserved = (pMask->rgbRed + pMask->rgbGreen + pMask->rgbBlue) / 3;
				pRGB->rgbRed = pSrc->rgbRed * pRGB->rgbReserved / 255;
				pRGB->rgbGreen = pSrc->rgbGreen * pRGB->rgbReserved / 255;
				pRGB->rgbBlue = pSrc->rgbBlue * pRGB->rgbReserved / 255;
			}
			return hBitmap;
        }
        if (hBitmap) ::DeleteObject(hBitmap);
    }
	if (srcInfo) freeBitmap(srcInfo);
	if (maskInfo) freeBitmap(maskInfo);
    return NULL;
}

void Paint(HDC hdc) {
	RECT rcSrc = { 0, 0, 80, 80 };
	RECT rcMask = { 100, 0, 180, 80 };
	RECT rcRes = { 200, 0, 280, 80 };

	auto bmpSrc = loadBmp("t\\src.bmp");
	auto bmpMask = loadBmp("t\\mask.bmp");
	auto bmpRes = calculateBmp(bmpSrc, bmpMask);

    draw_bitmap(hdc, bmpSrc, rcSrc);
    alpha_draw_bitmap(hdc, bmpMask, rcMask, false);
    alpha_draw_bitmap(hdc, bmpRes, rcRes, true);

	freeBmp(bmpSrc);
	freeBmp(bmpMask);
	freeBmp(bmpRes);
}